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  • 1
    Publication Date: 2019-03-04
    Description: The boron isotope (δ11B) composition of marine calcifiers is considered to be one of the most reliable pH proxies, enabling us to reconstruct past ocean pH and infer on the associated changes in carbon budget involved (e.g. Gut- jahr et al. 2017). The application of the commonly used δ 11 B archives such as foraminifera or corals is however mostly limited to the Cenozoic due to insufficient preservation or incomplete geological records. Brachiopods have a promising potential for extending our knowledge on seawater pH evolution throughout the entire Phanerozoic considering their high abundance in the fossil record and its origin dating back to the early Cambrian. Moreover, their shell is composed of low-magnesium calcite, rendering brachiopods more resistant to post-depositional di-magenetic alteration of its primary chemical signal (e.g. Brand et al. 2012). Additionally, even today they present an extant and widespread taxa, allowing for an assessment of the controls on boron isotope incorporation into brachiopod calcite and possible distortions of the signal due to vital effects or other processes. We present a detailed exploration of boron isotope systematics in three different brachiopod species (Magellania venosa, Terebratella dorsata, Pajaudina atlantica) cultured under controlled laboratory settings for over a year. Our experimental setup includes a control (pH = 8.15) and two pH treatments (pH = 7.6 and 7.35), and we provide both bulk MC-ICP-MS as well as high spatial resolution SIMS data of the shell material. Our results indicate that boron incorporation is primarily driven by vital effects related to their ability to regulate calcifying fluid pH in response to ambient changes, which we further validate by in vivo microelectrode measurements (e.g. Stumpp et al. 2012). Despite internal buffering, the local pH at calcification sites systematically decreases with seawater pH, and hence is impacted by ocean acidification. This not only suggests that brachiopod shells serve as useful and conservative recorders of past ocean pH trends, but also provides new insights into mechanisms that may have enabled brachiopod survival throughout several major environmental crises in the past. Our findings have implications for past climate studies, as well as research on calcification processes and physio- logical adaptations to environmental change (e.g. the actual global ocean acidification). Brand, U., Posenato, R., Came, R., Affek, H., Angiolini, L., Azmy, K. and Farabegoli, E., 2012. The end-Permian mass extinction: A rapid volcanic CO2 and CH4-climatic catastrophe, Chem. Geol. 323, 121-144. Gutjahr M., Ridgewell A., Sexton P.F., Anagnostou E., Pearson P.N., Pälike H., Norris R.D., Thomas E., and Foster G.L., 2017. Very large release of mostly volcanic carbon during the Palaeocene-Eocene Thermal Maximum, Nature 548, 573-577. Stumpp M., Hu M.Y., Melzner F., Gutowska M., Dorey N., Himmerkus N., Holtmann W.C., Dupont S.T., Thorndyke M.C., and Bleich M. Acidified seawater impacts sea urchin larvae pH regulatory systems relevant for calcification, PNAS 44: 18192-18197.
    Type: Conference or Workshop Item , NonPeerReviewed
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  • 2
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    In:  Arch. Gartenbau 4, Heft 4; p.277-278
    Publication Date: 1956
    Description: Auf der Basis von Messungen mit Apfelwicklerkontrollkästen wurden unter anderem anhand von Korrelationsanalysen der Einfluß der Temperatur auf das Schlüpfen des Apfelwicklers, sowie den Apfelwicklerflug untersucht. Als Ergebnis wird unter anderem eine Temperatursummenregel präsentiert. KATASTER-BESCHREIBUNG: Temperatursummenregel für den Massenflug der ersten Apfelwicklergeneration im Jahr. KATASTER-DETAIL: Mit dem Beginn des Massenfluges der ersten Generation ist zu rechnen, wenn ab einer Temperatursumme von 283°C (Basis 6°C) ab Huflattichblüte bzw. 136°C (Basis 8°C) ab Stachelbeerblüte niederschlags- und windarme Tage mit Tagesmitteltemperaturen 〉=15°C auftreten.
    Keywords: DDR ; 1953-1955 ; Apfel ; Pflanzenschädling ; Obst
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  • 3
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    In:  Arbeiten aus der biologischen Bunbdesanstalt für Land- und Forstwirtschaft 14, Heft 1; Parey, Springer, Berlin; p.1-76
    Publication Date: 1925
    Description: Detaillierte Auflistung des Maikäferauftretens verschiedener Jahre aus dem Zeitraum 1900-1920 aus ganz Deutschland in Bezirks- teilw. sogar Gemeindeauflösung wird gegeben. Der Einfluß der Temperatur in Form von 9°C Mitteltemperatur als Grenze für die Generationenanzahl der beiden Maikäferarten Melolontha melolontha L. und Melolontha hippocastani F. wird diskutiert. Eine Karte über die Generationsdauer der beiden Maikäferarten im deutschen Reich, teilweise auf Bezirksebene, ist enthalten. KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Keywords: Deutschland ; 1855-1923 ; Forst ; Pflanzenschädling
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  • 4
    Publication Date: 2018-06-11
    Description: Home Plate is a layered plateau in Gusev crater on Mars. It is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. A coarse-grained lower unit is overlain by a finer-grained upper unit. Textural observations indicate that the lower strata were emplaced in an explosive event, and geochemical considerations favor an explosive volcanic origin over an impact origin. The lower unit likely represents accumulation of pyroclastic materials, while the upper unit may represent eolian reworking of the same pyroclastic materials.
    Keywords: Lunar and Planetary Science and Exploration
    Format: application/pdf
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  • 5
    Publication Date: 2018-06-08
    Description: This paper presents the status of the long-term experiment using a hybrid GPS/acoustic system to determine strain rates across the Cascadia subduction zone.
    Format: text
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  • 6
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    In:  Other Sources
    Publication Date: 2018-06-08
    Description: In this paper we review the IGS network as it currently exists and its effectiveness in supporting the IGS suite of precise products.
    Keywords: Geophysics
    Type: International GPS Service (IGS) 2002 Workshop Towards Real Time; Ottawa, Ontario; Canada
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  • 7
    Publication Date: 2013-08-31
    Description: Developing flows in two out-of-plane double S-bend configurations have been measured by laser-Doppler anemometry. The first duct had a rectangular cross-section 40mmx40mm at the inlet and consisted of a uniform area 22.5 deg. - 22.5 deg. S-duct upstream with a 22.5 deg.- 22.5 deg. S- diffuser downstream. The second duct had a circular cross-section and consisted of a 45 deg. - 45 deg. uniform area S-duct upstream with a 22.5 deg. -22.5 deg. S-diffuser downstream. In both configurations the ratio of the mean radius of curvature to the inlet hydraulic diameter was 7.0, the exit-to-inlet area ratio of the diffusers was 1.5 and the ducts were connected so that the centerline of the S-duct lay in a plane normal to that of the S-diffuser. Streamwise and cross-stream velocity components were measured in laminar flow for the rectangular duct and in turbulent flow for both configurations; measurements of the turbulence levels, cross-correlations and wall static pressures were also made in the turbulent flow cases. Secondary flows of the first kind are present in the first S-duct and they are complemented or counteracted by the secondary flows generated by the area expansion and by the curvature of the S-diffusers downstream. Cross-stream velocities with magnitudes up to 0.19 and 0.11 of the bulk velocity were measured in the laminar and turbulent flows respectively in the rectangular duct and six cross-flow vortices were evident at the exit of the duct in both flow cases. The turbulent flow in the circular duct was qualitatively similar to that in the rectangular configuration, but the cross-stream velocities measured at the exit plane were smaller in the circular geometry. The results are presented in sufficient detail and accuracy for the assessment of numerical calculation methods and are listed in tabular form for this purpose.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA-CR-176981 , FS/86/30 , NAS 1.26:176981
    Format: application/pdf
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  • 8
    Publication Date: 2015-01-14
    Type: Report , NonPeerReviewed
    Format: text
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  • 9
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    In:  Environmental Modeling and Assessment, 17, 1-2
    Publication Date: 2011-08-04
    Type: paper
    Format: application/pdf
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  • 10
    Publication Date: 2011-10-25
    Type: thesis
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